Process for drying oleaginous seeds



1933" H I QZQfiiw EZ PROCESS FQR. DRYITIG OLEAGINOUS SEEDS AND FRUITS Filed March 25,1931 2' Sheets-Sheet l Oct. 10, 1933. H J HUTTEMAN 1,929,691

PROCESS FOR DRYING OLEAGINOUS SEEDS AND FRUITS Filed March 25, 1931 2 Sheets-Sheet 2 Patented Oct. 10, 1933 PATENT OFFICE PROCESS FOR DRYING OLEAGINOUS SEEDS AND FRUITS Hermanus Jansen Hutteman, Soerabaya, Dutch East Indies Application March 25, 1931, Serial No. 525,281, and in the Netherlands April 16, 1930 3 Claims.

The invention relates to a process for drying oleaginous seeds and fruits having a high percentage of water, especially coprah.

The usual methods of drying coprah consist therein, that this material in the form of lumps is subjected to the sun which is a rather long process, or that it is dried by conducting heated air along the same.

According to the invention another method for removing the water is applied which consists therein that the material in more or less finely divided condition is brought into oil of such a temperature that the water is boiled away from the starting material. This process has important advantages with regard to the known methods, because by proceeding so the removal of the water takes place very quickly, and moreover the heating of the material takes place without contact with the air.

In the known methods often a heating takes place during a rather long period at the air, by which the quality of the coprah so treated decreases, so that the coconut oil obtained by pressing this coprah generally is of bad quality and must be made suitable for consumption by a complete refining consisting in eliminating acid by means of lye, bleaching with bleaching earth or other discolorizing agents, and a deodorizing by means of steam.

According to the invention however, the removal of the water takes place quickly and under such circumstances that a decrease in quality of the coprah does not take place or in a much smaller degree so that a much better oil is obtained.

The treatment in the hot oil may also be carried out at another pressure than the atmospheric pressure, namely at a reduced pressure. In this case the water will boil away at a lower temperature, so that a heating much below 100 C. will be suificient. It is self-evident that in this way a product of much better quality will be obtained because the material will sufier less by heating. So for instance if a reduced pressure is applied, a much smaller discoloration will take place. This discoloration which perhaps will be due to a decomposition of the albumen is always much smaller, according to the present process than with the usual drying at the air. Under normal circumstances the grated coprah cannot .be brought above 70 without a serious discolorizing taking place. After heating under oil this discolorizing was of no importance even at 105410".

Furthermore the process may be carried out continuously or discontinuously. In general a continuous process will be preferred because in that case always a relatively small quantity of material is in touch with the hot oil, so that the heating time will be smaller again. while also for economical-technical reasons a continuous process is desirable.

As the oil in which the material to be dried is brought, preferably the same oil will be chosen which is obtained later on from the same by pressing. So e. g. coprah must be dried by bringing the more or less finely divided coprah into hot coconut oil. The invention, however, may also be applied by choosing for this purpose another oil, if the mixing which necessarily will occur will not cause any difficulty. In order to decrease the discolorizing still further, the starting material, preferably in comminuted condition, may be subjected to a treatment with a salt solution. To this purpose the material is left during some hours in a weak salt solution, and then the liquid is enabled to drip out. It appeared that coprah which was so pretreated practically did not discolorize during the drying process, so that even at a rather high temperature of the oil during the drying, the coprah remained fully blank.

Figure 1 is a cross sectional view of an apparatus designed to carry out the process,

Figure 2 shows the supply part of a modification of the apparatus,

Figure 3 shows a part of the modification illustrating the heating elements, and

Figure 4 shows the exhaust part of the modification shown in Figures 2 and 3.

The process may be carried out in the device indicated in Fig. 1.

This device comprises two open containers which are partly filled with oil and the cylindrical- 1y closed vessel 3. The Vessel 3 communicates with the container 1 by means of the tubes 6 and '7 in which a transporter 8 is found, and with the container 2 by means of the down pipe 4 and moreover it is connected by means of the tube 5 with a condenser and an air pump. In the vessel 3 a vacuum of e. g. 0.3 atm. absolute is maintained, so that the oil rises through the tube 6, '7 and 4 until a level h which is determined by the pressure below atmosphere in the vessel 3. The tube 6 and the vessel 3 are provided with steam jackets for the heating of the oil, and if desired also the container 1 may be heated.

The comminuted coprah is supplied regularly to the container 1, and from there it is moved upwardly by means of the transporter 8 through the tube 6. The oil in the container 1 may have a temperature of 'e. g. '70-80 so that the water 110 here does not yet boil from thematerial, but only after being transported upwardly along a certain distance. As soon as the coprah will have reached a level at which the pressure is sunk so far that the boiling point of water belonging to that pressure is lower than the temperature of the oil, a development of steam will take place. This steam escapes through the vessel 3 to the tube 5, and is conducted to the cooler. According to the coprah being further conducted upwardly, the development of steam takes place more easily in agreement with the decreasing pressure. Now the circumstances must be so chosen, that the coprah which reaches the top of the vessel 3, will be dried up to the desired percentage of water, which may be obtained by regulating the temperature, the vacuum, the speed of the transporter and the like.

The dried coprah falls through the tube 4 into the container 2 and is conducted continuously through the transporter 9 to the spiral tube 10 which ends above the presses. In the transporter 9 the adhesive oil may drip from the grated material.

Another embodiment of a drying device according to the invention is shown in the Figs. 2-4.

This device comprises a supply part shown in Fig. 2, and an exhaust part shown in Fig. 4. Between these two one or more heating elements are found, which are shown in Fig. 3. The heating elements are tubular and provided with the steam jacket 11, with a steam supply 12 and a steam exhaust 13. The heating elements are arranged in an inclined position, so that they may always remain filled with oil until the level shown in Fig. 3. The material to be dried is stirred with oil (forv coprah e. g. coconut oil), in a container 1, and aspired by the tube 14 into the part 15 of the first heating element 16. The supply may be regulated by providing the tube 14 at the bottom with a cover with larger or smaller opening. The tube 17 and the pump 18 serve for preventing the level of the oil to rise above the desired height, the partition 19 serving for preventing the material to be dried from entering into the tube 1'7. If the material to be dried is lighter in weight than the oil, the tube 17 must end in the lower part of the heating element 16.

Now the coprah is moved by means of the transporting screw through the heating element during which the water will boil away by the hot oil; the material will then fall at the left end through the connection tube 20 into the following heating element. At its higher point each heating element is provided with a connection to a mutual vacuum conduit 21 leading to the con densor so that in all heating'elements the same pressure will be found. This pressure is chosen as low as possible, not only because at a low temperature the material practically will not be subjected to discolorizing, but also in order to make the difference in temperature with the steam jacket as large as possible. Owing to the inclined position of the heating elements, the material will never be under the pressure of a high liquid column.

For discharging the dried material the part of the device indicated in Fig. 4 is used. The material falls from the last heating element through the tube 22 into the rotating slide valve 23 and from there into the transporting screw 24, which is filled with oil up to the level indicated in the drawing. Through the sliding valve 23 oil is supplied regularly into the tube 22; as soon as the level in this tube will rise above the tube 25, the

excess is returned by the pump 26 to the container 2'7, which is connected with the transporting tube 24 by the tube 28. In the top part of the tube 24 the oil may drip from the material, which then arrives in a tube 29 for being further dealt with. The opening of the tube 25 must be kept free from the falling solid material.

In the described way the percentage of water in the coprah may be brought easily below 3%, which has a special advantage for an extraction plant, while moreover owing to the rapid drying the further treatment will lead to obtaining an oil with a low percentage of fatty acid.

The whole apparatus only takes a small space, and if desired may be arranged at the wall. At the same time it may be used as a transporting device, if the place of receipt of the material to be dried is situated at some distance from the manufactory.

If the fuel is'dear, steam may be saved by Br'iiden-compresses. In that case it is advisable to supply fresh steam of high temperature to the first heating element, in order to carry out the drying more quickly. In the first heating element the high temperature will not cause any difiiculty, owing to the high percentage of water of the material.

If a compact arrangement is preferred, the heating elements may also be arranged one above the other.

In general it is preferable to transport the coprah leaving the oil immediately to the presses or wringers so that the whole manipulation from the fresh fruit pulp until the pressed oil only takes a short time. In this way a considerable 11D improvement of the quality of the oil with regard to the crude coconut oil obtained in the usual way is reached.

The above described devices are only given by way of example and may be varied in many ways. 115

Although the invention is of importance in the first place for drying coprah, it may also be applied for drying other oleaginous starting materials for instance palm fruits.

I claim:-

1. A process for drying oleaginous seeds and fruits comprising submerging the preferably comminuted material in heated oil and subjecting the mixture to a vacuum, the temperature of the heated oil being higher than the boiling point 125 of water at the vacuum pressure.

2. A process for drying oleaginous seeds and fruits comprising introducing the material into a container withheated oil, conveying the material continuously in an upward direction by means of an evacuated transporter, causing the dried material to fall from the top of the transporter and removing the material through a down pipe preferably provided with a closing device, the temperature of the heated oil being higher than the boiling point of the water at the vacuum pressure.

3. A process for drying oleaginous seeds and fruits comprising introducing the material into a container with heated oil, conveying the material continuously by means of a plurality of evacuated ascending transporters, causing the material to fall from the top of each transporter to the lowest part of the subsequent transporter and removing the material through a down pipe preferably provided with a closing device, the temperature of the heated oil being higher than the boiling point of the water at the vacuum pressure.

HERMANUS JAN SEN HUTTEMAN. 

